Automated material handling systems have been used for many years for transferring manufactured objects from one location to another. These systems typically include a manipulating device, such as a pick-and-place unit, a robot, or a linear motion device, having a gripping device attached thereto for grasping objects that must be transferred from one location to another. In some material handing systems, the gripping devices are in the form of vacuum heads, which utilize vacuum pressure for grasping the objects. The vacuum pressure in these systems is typically generated through a compressed air/Venturi-based vacuum generator and applied through polymeric suction cups. The manipulating devices may include one vacuum head, or a plurality of vacuum heads connected together for providing the material handling system with the flexibility of transporting objects of varying sizes, weights, shapes, etc., or transporting multiple objects simultaneously.
Material handling systems as just described perform well, provided that the leakage between the object to be moved and the vacuum head is limited. Typically, one vacuum generator is used per vacuum head. However, some systems are configured where one vacuum generator is connected to multiple vacuum heads. In such systems, the risk of vacuum loss to the other vacuum heads increases if one or more vacuum heads does not have a proper seal against the object or objects to be transported.
In these systems where multiple vacuum heads are used, there is a need to control the vacuum loss present in such vacuum heads that does not obtain or maintain an adequate gripping or grasping force between the vacuum head and the object(s) to be moved.